Hardness testing machine



Sept. 12, 1950 E.H.SHAFF HARDNESS TESTING MACHINE Filed Nov. 9, 1948 3 Sheets-Sheet l Q WW/7 5? HVVENTUR.

- @MEM ATTORNEY.

iatentecl Sept. 12, 1950 OFFICE HARDNESS TESTING MACHINE v Ernest Shaft, Spring Lake, Mich. Application November 9, 194.8. Serial no. 59,055 i 1 This invention relates to hardness testing machines. I The principal objects of this invention are: i First, to provide a machine for testing the hardness of objects such as grinding wheels 17 Claims. (01. 7s '1 improvements in v which machine will cause a bit to deliver a predetermined number of equal impact blows against the object being tested and which will measure the depth ofpenetration of the bit into the ob.

ject after delivering the series of blows;

Second, to provide a hardness testing machine having an impact bit with means for progressively rotating the bit so that each successive blow of the bit isapplied at an angularly differeiit position on the object being tested.

Third, to provide a hardness testing machine witha gravity operated bit and vacuum mechanism for raising the bit for each successive blow; Fourth, to provide a valve'mechanism for a vacuum elevated bit which mechanism will assure rapid release of the bit at the same elevation during a series of strokes of the bit.

Fifth, to provide a hardness testing machine with vacuum operatedmechanism for raising an impact bit and rain to an elevatedposition, said vacuum mechanism being controlled to raise said ram and bit to a uniform height whereby the force of the falling bit and the penetration thereof can be used as a standard for measuring the relative hardness of objects against which the bit is directed Sixth, to provide a hardness testing machine with vacuum operated mechanisms for raising a ram and for rotating the ram slightly during its up stroke, said mechanisms having individual and independent vacuum relief passages and valves.

Seventh, to provide 'interconnectedvalve actuating mechanism and automatic stop mechanism fora vacuum reciprocated and rotated ram which will positively lock the ram against rotary tester.-

Figs. 3, 3A, 4 and 5, the mechanism being shown at the end of a testcycle. v

j Fig. v 3;is a top plan view of the body of the Fig. 3A is a top plan view of the tester and its supporting stand,. portions of the stand being broken away in horizontal cross section.

. Fig. 4 is a vertical cross sectional View through the body and base of the tester, the section being taken along the plane indicated by the broken line ie-4, in Figs. 3 and 5 with the tester in shut ofip'osition. 1

Fig, 5 is a horizontal cross sectional view through the body of the tester taken along the plane indicated by the line 5-5 in Figs. 4 and '7.

Fig.6 is a vertical transverse cross sectional view taken along the plane of the line 6-6 in motion at the end of its rotary cycle while permitting one succeeding reciprocation of the ram. 2 Other objects and advantages relating to details of my invention will be apparent from a consideration of the following description and claims.

The drawings of which there are three sheets illustrate a preferred form of my tester.

Fig. 1 is a fragmentary front elevational View of the tester partially broken away in transverse vertical cross section along the plane'indicated by the line |-=l in Fig. 2, the mechanism being shown at the'bottom on an operating stroke. I

Fig. 2 is a side elevational view of the tester partially broken away in vertical longitudinal cross section along the plane of the line 2-'-2 in Figs. 5 and 9 and with the tool carrying ram and rotatingmechanism removed.

Fig. 7 is a verticallongitudinal cross sectional view through the body of the tester taken along the plane of line 1-1 inFig- 5. f Fig. 8 is a fragmentary vertical cross sectional view through the body and base of the tester i1- lustratingthe mechanism for rotating the ram and taken along the plane of the line 8 B in Fig. 9.

Fig. 9 is a horizontal cross sectional View through the body of the tester taken along the plane of the line 9-9 in Fig. 8.

The tester includes generally a stand! having an adjustable front extension 2 mounted on the slide rods 3 and a support or anvil 4 for support+ ing an object to be tested such as thegrinding wheel indicated at 5 in Fig; 2. Thestand I carries a pedestal 6 along which the sleeve 1 is vertically adjustable. The pedestal 5 carries a rack 8 and the sleeve '1 is provided with an ad justing" hand wheel 9 having a pinion l0 en.- gageable with the rack for vertically adjusting the sleeve on the post. A locking hand wheel has its shaft l l threaded into the sleeve 1 for engage ment with the pedestal 6 to lock the sleeve in its adjusted position. The sleeve '5 is provided with a forwardly extending arm, 12 having a flat vertical face to which the operating mechanism of it carries on its forward face micro-gage H. having the actuating plunger 58. A lever i9 is and base l4 it will be noted that the body |3 defines a vertical bore or cylinder 2| within which the upper piston-like portion 22 of the.=-ram |5 is received. The top of the cylinder 2| is closed by the plate-like cylinder head 23. "The side of the body l3 defines a threaded port 24 for receiving the coupling 25- through which a supply of compressed air may be applied to the machine. The port 24 opens into a vertical passage 26 extending-downwardly adjacent to the horizontal bore 27 along one side of the body. The flow of compressed air through the passage 26 is controlled by the valve 28 actuated by the depending valve rod 29. Air admitted through the valve 26 isdirected to the bore 21 by the oblique passage 36. A asket 3| at thebottom of the passage 26 prevents the escape of the compressed air through the bottom of the inlet passage. I j The horizontal bore 21 as is more clearly illustrated in Fig. 4 is shouldered as at 32 to receive the reduced end of the Venturi plug 33. The rear or. outlet end of the bore 21 is provided with a discharge coupling 34 and the front end of the bore is closed by the plug 35. Compressed air entering the bore 21 from the passage 36 is directed through the nozzle in the Venturi plug in a well known manner to create an area of low pressure at the throat of the Venturi. tester is provided with a vertical passage 36comniunicating with the throat of the Venturi through a suitable passage in the Venturi plug 33 and extending upwardly to the top of the body l3. rhe top face of the body 13 is grooved as at 3'! (see Fig. 2) to form a connecting passage between the vertical passage 36 and the upper end of the cylinder 2 The groove 31 is closed on the upper side by the head gasket 38 and cylinder head 23. An adjusting screw 35 extending through the head 23 into the passage 36 serves as a. metering pin for determining the size of the opening between the passage 36 and the cylinder 2|} parent that compressed air admitted to the body of .the tester will create an area of low pressure in the Venturi to draw a partial vacuum in the upper end of the cylinder 2| to raise the piston 22 and the ram l5. When the piston reaches the top'of its stroke it will engage the lower end 40 of the valve 4| extending through :a port in the cylinder head 23. Opening of the valve 4| will of course break the vacuum in the cylinder 2| and permit the piston and ram to fall.

At the lower limit of travel of the piston 22, the piston will engage the finger 42 of the valve closing rod 43 which extends upwardly through a passage 44' provided therefor along side of the cylinder 2|. The valve closing rod 43 extends upwardly through the sleeve 44A and the bar link 45 and is provided with a nut and spring 46 -for urging the link 45 downwardly. The link 45 rests upon the valve lifter 4'? engaging the top of the valve 4| to securely seat the valve so that the machine will immediately commence to re- 12, 7, 8 and 9).

4 establish the vacuum in the cylinder 2|. The valve lifter 41 is engaged with a notch or groove in the valve 4| so that during operation of the tester, lifting of the valve 4| by the cylinder will also lift the valve lifter 41, link 45 and closing rod 43. It will be noted particularly from Fig. 7 that the valve lifter slides upon the upper end of sleeve 44A and is independent of the action of rod 43 except through the spring 46.

In order to rotate the ram l5 between each stroke there is provided between the piston portion 22 and ram l5 a ratchet wheel 48 (see Figs. The ratchet wheel 48 is located in a recess 49 formed in the under face of the body'l3 and coaxial with the cylinder 2|. The

ratchet wheel 4'8 is positioned around a central portion :50 of the ram which is of reduced diameter and which is provided with vertically extending grooves 5| in which the pins 52 carried by the-ratchet wheel are engaged. The ratchet 'wheel is retained within the recess 49 by a pro jection53'on the top of the base l4. Aball bearing 54 suipports the ratchet wheel on the projection 53 so that the ratchet is-freely rotatable thereon. r

The mechanism for rotating the ratchet'wheel 48 consists of ahorizontal piston 55 reciprocable in a cylinder 56 extending transversely through The body of the a the body i3 behind the recess 49, and opening tangentially to the recess. The piston 55 carries the horizontally projecting spring pressed dog 51 which is engageable with the teeth 58 of the ratchet. wheel each time the piston 55 is actuated. The piston 55 is spring pressed by the spring 59 to advanced position and is arranged to be retracted to the right as shown in Figs. 4 and 9 by the introduction or establishment of a partial vacuum behind the piston. The pin 60 projecting from the outer end of the piston 55 is used as a visual indicator to show when the piston is operating correctly.

In order to establish the vacuum in the cylinder 56 the body I3 is provided with a passage 6| comalong side of the valve closing. rod 43.

munic'ating with the Venturi throat on the opposite side ofthe throat from the passage 36. The passage 6| is connected to the cylinder 56.by the horizontal bore 62 and vertical passage 63, the bore 62 being closed by a plug at its outer end (see Fig. 4) The vacuum in the cylinder 56 is broken through a passage 64 (see Figs. 5 and 6) extending between the passages 63 and 62 and a vertical relief passage 65 extending upwardly The-cylinder head 23 is provided with a port communicating with the relief passage 65. A relief valve 66 similar to the valve 4| for breaking the vacuum in the cylinder 2| is provided for closing the passage 65. Both of the valves 4| and 66 are connected by the valve lifter- 41 so that opening of the valve 4| will concurrently open the valve 66.

It will thus be apparent that both the main piston 22 and the ratchet advancing piston 55 Will be retracted at the same time by the vacuum created by the Venturi. When the main piston reaches the top of its stroke it will break the vacuum behind each piston permitting both pistons to advance. The retracting motion of the piston 55 advances the ratchet wheel 48 through the angular space of one of the teeth 58 while the main piston 22 is being lifted.

In order to stop the ram and bit after a predetermined number ofstrokes, the undersurface of the ratchet Wheel 48 is provided with a detent 6'! (see Fig. 7) within which the pin 68 is enbody I3 and is pivoted as at within'a" slot provided therefore in the extension 53 of the base I 4. The innerend of the lever 69 engages the lower end of the valve rod 29 so that, depressing the outer end of'the release lever 69 will disengage the pin. 68 from the detent and also open the valve 28. A stop rod 'llzengages thereleas'e lever 69 outwardly of the pivot Ill and extends upwardly through the sloping bore "provided therefore in the body It (see Figs. land '7). The stop rod. ll extends upwardly through thecylinder head 23 and has a pair of nuts 'l3 threaded thereon in spaced relationship .to form a lost ,inotion liftingconnection with the link #5. Raising of the stop rod engages the lower nut 13 with the link tiand relieves the valve lifter 41 from the pressure .of the spring 46 and valve closing rod 43 (see Fig.

The cycle of operation of the tester is as follows:

The work piece to be tested is placed on the anvil 4 and clamped in place by lowering the body l3 until the foot 20 engages the workpiece. The valve 28 being closed there will be no vacuum H and 66 willopen-and remain open because the release lever 69'and stop rod ll have taken the pressureof spring 46 ofi the valves as previously explained. The-piston 22: and ram will thenmake their final down stroke and come to restso that a, reading can be taken on the gageIl.

It will be noted that the machine automatically completes a cycle of operation and, stops after having been manually started and that each stroke of the, ram and bit will be fromthe in the machine and the ram and bit will be ina v lower position to engage the surface of the work piece so that a reading maybe. taken on the gage l1. Preferably the gage is provided with an adjustable dial so that it can be setto zero reading. The release lever 69 being in raised,

or off position, the relief valves 4! and 65 will be relieved of the pressure of spring 46- and will be open due to frictional engagement between the-lifter 41 and sleeve 44A. The. pin 68 will be engagedv with the detentfil. The operator can now press downwardly on the release lever 59 to release the pin 68 and open the valve 23.

The spring 46 and link 45 then operates on the valve lifter 41 to close the relief valves. The machine will then commence to operate aspreviously described to deliver a series of blows to the work piece and to angularly advance the ram and bit between each stroke by operation of the ratchet wheel 48. On each up stroke of the ram opening of the valve 4| and raising 'of the valve lifter 41 will, move the free end of'the,

link 45 between the nuts 13 on the stop rod ll but this, motion will not, afiect the stop rod because of the lost motion of the link 45 between thenuts l3 and because ofthe pin 68 engaging the undersurface of the ratchet wheel. I

'When the ratchet wheel and ram have made a complete revolution the pin 68 will again become aligned with and fall into the detent 61. Movement of the release lever 69 and pin 63 is caused by air pressure acting on the valve" 28 in the inlet passage 26, the pressure beingsufficient to lower the rod 29 and close valve 28 when the pin 68 registers with the detent. V

The length of stroke of the horizontalpiston 55 is much less than the stroke of the ram l5 so the ratchet wheel 48 will be locked and the valve 28 will be closed before the ram has completed its last up stroke. It will be noted that the passage 26 is considerably larger than the passage 30 thus forming a reservoir 14 below the valve 28. 'This reservoir contains enough air under pressure after the valve 28- is closed-to continue to cause the'venturi to create. enough vacuum -in-the cylinder 2| to complete the last upstroke of the ram and piston 22.

When the piston strikes the valve 4 l, the valves same elevation relative to the workpiece so that the degree of penetration of thebit will be a measure of the hardness of the work piece.- By using a bit of specified size and shape the machine :can be used as a standard measure for.

comparing the hardness of different types-of materials.v

In order that the gage I! and lever l9 will not be subjected to the impact shock'ofthe ram, the gage is mounted on a pivot 15 and springs .16, and 16A, each having one endsecured to the pin 18, bias the gage and lever out of operative engagement with the ram. ,Springlfi acts under tension to lift upon the outer end of thelever,

and spring 16A, acting under compression on the backof the gage, tilts the gage upwardly about its pivot. To take ajreading the gage is pushed downwardly into, engagement with the stop Tl underneath the pivot support for the gage (see Fig. 2). n j Having thus described my invention what'I claim as new and desire to secure by Letters Patent is: i: 1. A hardness tester comprising, a stand, a body vertically adjustably mounted on said stand and having a depending foot adapted to clamp a work piece on said stand, said body defininga vertical cylinder therethrough, a ram reciprocable in said cylinder and having a bit on the lower end thereof adapted to strike said work piece, a head closing the upper endof said cylinder and defining a port opening to said cylinder, a high pressure air passage through said body and having a venturi therein, a low pressure passage communicating between the throat of said ven turi and the top of said'cylinder, a valve for closing said port in said head and having a pro jection engageable with said ram at the upper limit of movement thereof to open said valve and relieve the low pressure in said cylinder, a valve closing rod slidable in said body and engageable with said ram at its lower limit oftravel to close said valve, a ratchet wheel mounted in said body and non-rotatably and slidabl'y secured to said ram, a second cylinder formed in said body tan; gential to said ratchet wheel and having a tool advancing piston therein, a pawl on said piston sprin pressed into engagement with said ratchet wheel, a second low pressure passage in said body extending between said venturi and said second cylinder, a spring for advancing said piston, a relief passage in said body communicating between said second low pressure passage and the exterior of said body, a relief valve for said relief passage and positioned on the opposite side of said valve closing rod from said first valve, .a valve lifter connecting said valvesv for simultaneous opening and closing motion, said valve closing rod extending through said-valve lifter and having a spring on its upper end for yield-' ingly urgin said lifter downwardly, an air valve in said air passage, a lever for openingsaid air valve, a pin on said lever engageable with said ratchet wheel, a shut-off rod extending from said shut-01f rod whereby said shut-off rod is not affected by opening motion of said relief valves but is operable to lift said link and said spring from said valve lifter, said ratchet wheel having a recess formed therein to receive said pin in a stop position of said wheel thus permitting said lever to move to shut-off position under the influence of air pressure on said air valve, said air passage including a reservoir between said air valve and said venturi to supply air under pressure to operate said venturi after said air valve is closed and complete the final up stroke of said ram, and a gage on said body arranged to measure the position of said ram relative to a fixed point on said body. i

' '2. A hardness tester comprising a body vertically adjustably mounted and adapted to' be positioned over a work piece, said body defininga generally vertical cylinder therethrough, a ram reciprocable in said cylinder and having a bit on the lower end thereof adapted to strike a work piece, a head closing the upper end of said cylinder and defining a port opening to said cylinder, a high pressure air passage through said body and having a venturi therein, a low pressure passage communicating between the throat of said venturi and the top of said cylinder, a first relief valve for closing said port in said head and having a projection engageable with said ram at the upper limit of movement thereof to open said valve and relieve the low pressure in said cylinder, a valve closing rod slidable in said body and engageable with said ram at its lower limit of travel to close said valve, said rod having a yieldable connection with said valve, a ratchet wheel mounted in said body and non-rotatably and slidably secured to said ram, a second cylinder formed in said body tangential to said ratchet wheel and having ,a tool advancing pistonvtherein, a pawl on said piston spring pressed into engagement with said ratchet wheel, a second low pressure passage in said body extending between said venturi and said second cylinder, a spring for advancing said piston, a relief passage in said body communicating between said second low pressure passage and the exterior of said body, a second relief valve for closing said relief passage, a valve lifter connecting said valves for simultaneous opening and closin motion, an air valve in said air passage, a lever for opening said air valve, a projection on said lever engageable with said ratchet wheel in the closed position of said air valve and lever and lockingly engaged with said wheel in the starting position of said wheel, a shut-off rod extending from said lever to adjacent said valve lifter, and a link fixed at one end and extending over said valve lifter to said shut-off rod whereby raising said shut-off rod and said lever will relieve said valve lifter and relief valves from the pressure of their yieldable connection to said valve closing rod, said high pressure air passage having a reservoir communicating therewith between said air valve and said venturi. l

,3'.-A hardness tester comprising a body defining a generally vertical cylinder therein, a ram reciprocable in said cylinder and having a bit on the lower end thereof adapted to strike a work piece, ahead-wall closing the upper end of said cylinder and defining aport openingto said 'cyl- 8v inder, a high pressure air passage through'said bodyand having a venturi therein, a low pressure passage communicating between the throat of said venturi and the top of said cylinder, a first relief valve for closing said port in said head wall and having a projection engageable with said ram atthe upper limit of movement thereof to open said valve and relieve the low pressure in said cylinder, a valve closing rod slidable in said body and engageable' with said ram at its lower limit of travel to close said valve,-ratchet teeth carried by said ram and non-rotatable relative to said ram, a second cylinder formed in said body tangential to said ratchet teeth and having a tool advancing piston therein, a pawl on said piston engageable with said'ratchet teeth, a'sec 0nd low pressure passage in said body extending between said venturi and said second cylinder, a spring for advancing said piston, a' relief passage in said body communicating between said second low pressure passage and the exterior of said body, a second relief valve for closing said relief passage, a valve lifter connecting said relief valves for simultaneous opening and closing motion, an air valve in said air passage, a lever for opening said air valve, a projection on said lever movable into non-rotative relationship with said ram in the closed position of said air valve and lever and in the starting position of said ram, a shut-off rod extendin from said lever to adja-' cent said valve lifter, and a link extending from said shut-oi? rod to between said valve lifterand said valve closing rod whereby said valve closing rod is prevented from closing said relief valves when said air valve is closed.

4. A hardness tester comprising a body defining a generally vertical cylinder therein, a ram reciprocable in said cylinder and having a bit on the lower end thereof adapted to strike a work piece, a head wall closing the upper end of said cylinder and defining a port opening to said cylinder, a high pressure air passage through said body and having a venturi therein, a low pressure passage communicating between the throat of said venturi and the top of said cylinder, a first relief valve for closing said port in said head wall and having a projection engageable with said ram at the upper limit of movement thereof to open said valve and relieve the low pressure in said cylinder, a valve closing rod slidable insaid body and engageable with said ram at its lower limit of. travel, a spring interposed between said valve'closing rod and said relief valve to close said valve, a ratchet wheel on said body and nonrotatably secured to said ram, a second cylinder formed in said body tangential to said ratchet wheel andhaving a tool advancing piston therein, a pawl on said piston spring pressed into engagement with said ratchet wheel, a second low pressure passage in said body extending between said venturi and said second cylinder, a spring for advancing said piston, a relief passage in said body communicating between said second low pressure passage and the exterior of said body, a second relief valve for closin said relief passage, a valve lifter connecting said valves for simultaneous opening and closing motion, an air valve in said air passage, a lever for opening said air valve, means on said lever lockingly engageable with said ratchet wheel inthe closed'position of said air valve and lever, a shut-off rod extending from said lever to adjacent said relief valves, and lost motion connecting means between said shut-off rod and said valve closing rod whereby said shut-off rod will render said valve closing rod inoperative to close said relief valves when saidshut-off rod is raised.

5. A hardness tester comprising a body defining-a generally vertical cylinder therein, a ram reciprocable in said cylinder and having a bit on the lower end thereof adapted to strike a work piece, a head wall closing the upper end of said cylinder and defining a port openin to said cylinder, a high pressure air passage through said body and having a venturi therein, a low pressure passage communicating between the throat of said venturi and the topof said cylinder, a first relief valve for closing said port in said head and engageable with said ram at the upper limit oi movement thereof to open said valve and relieve the low pressure in said cylinder, a valve closing rod slidable in said body and engageable with said ram at its lower limit of travel to close said valve, a ratchet wheel mounted in said body and 'engageable with said ram to rotate said ram, a second cylinder formed in said body-tangential to said ratchet wheel and having atool advancing piston therein, a pawl on said piston engageable with said ratchet wheel, an air valve in said air passage, a lever for opening said air valve, means on said lever lockingly engageable with said ratchet wheel in the closed position of said air valve and lever, a shut-off rod extending from said lever to adjacent said relief valve, and lost motion connecting means between said shut-off rod and said valve closing rod whereby said shutan interlocking engagement in the off-position off rod will render said valve closing rod inoperative to close said relief valves when said shutoff rod is in air valve closing position.

6. A hardness testing machine comprising a body having a vertically reciprocable ram mounted therein, an air passage having means in said body for creating a partialvacuurn, a

passage in said body communicating between said vacuum creating means and the top of Said ram for retracting said rarn, a relief .valve actuated by said ram at its upper limit of travel for break ing said vacuum, mechanism actuated by said ram in its lowered position for closing said valve, a ratchet wheel arranged to rotate said ram, vacuum actuated means operative concurrently with the retracting motion of said ram for angularly advancing said wheel, a valve in said air passage, a starting lever for said air valve pivotally mounted on said body, said lever and said ram having an interlocking non-rotatable connection in the air valve closing position of the said lever and the starting position of said ram, and a connecting member operatively connected between saidlever and said mechanism whereby air valve closing motionof said lever will render said mechanism inoperativeto close said relief valve, said non-rotatable connection being biased toward locking engagement by air pressure on said air valve in partiallyadvanced positions of said ram.

7. A hardness testing machine comprising a body having a vertically reciprocable ram mounted therein, pneumatic means for creating a partial vacuum, a passage in said body cornable in partially advanced positions of said wheel.

8. A- hardness testing machine comprising a' body having a vertically reciprocable ram mounted therein, pressure means in said body ior creating a partial vacuum, a "passage in said body communicating between said vacuum creating-means and the top of said ram for retracting said ram, a relief valve actuated by said ram at it'supper limit of travel for breaking said vacuum, vacuum actuated means operative concurrently with the retracting motion of said ram for angularly advancing said ram, an air valve for controlling said pressure means, and a starting lever for said valve pivotally mounted on said body, said lever and said ram having an interlocking engagement in' the off-position of the said lever and one position of said ram, said lever and ram being non-lockingly engageable in partially ad'- vanced positions of said wheel to prevent movement of said lever to off position, said air valve being operative under air pressure tourge said lever toward on position. f

9. In a hardness tester having a body'mernber with a tool carrying ram reciprocably mounted therein, a high pressure air passage formed in said body and having a pressure reducing venturi positioned therein,.a ram rotating piston reciprocably mounted in said body and spring biased to an advanced position, a ratchet member carried by said ram and adapted to be engaged with said piston forangularly advancing said ram, a'pair of low pressure passages formedin said body and extending from the low essure area of said venturito the ends of said ram and said piston, a pair of relief passages opening between said low pressure passages and the exterior of said body, Valves for closing said relief pas sages, and valve actuating mechanism engage! able with said ram at the ends of its reciprocable motion for concurrently opening and closing said valves.

1 9. Ina hardness tester having a body member with a. tool carrying ram reciprocably mounted therein, a high pressure air passage formed in said body and having a pressure reducing means positioned therein, a ram rotating piston recip-j rocably mounted in said body and biased to an advanced position, a ratchet member carried by said ram and adapted to be en aged with said piston for angularly advancing said ram, a pairv of low pressure passages formed in said body and extending from theilow pressure area of said reducing means to the ends of said ram and said piston, a pair of relief passages opening between the ends of said piston and ram and the exterior ofsaid body, valves. for closing said relief passages, and valve actuating mechanism engageable 'imember for angularly advancing said ram, a pair of passages formed in said body and extending from the low pressure area of said reducing means said air passage to the ends of said ram and said member for retracting said ram and said member by fiuid pressure, a pair of relief passages opening between said pair of passages and the exterior of said body, valves for closing said relief passages, and valve actuating mechanism engageable with said ram at the ends of its reciprocable motion for opening and closing said valves.

12. A hardness tester comprising, a body having a pair of reciprocable members mounted therein, one of said members having a driving engagement with the other of said members to angularly advance the other of said members, passages formed in said body for applying a vacuum to said members to retract said members, said one member being spring advanced, said other member being gravity advanced, valves for venting said passages to break the vacuum therein. valve actuating mechanism engageable with said other of said members at the ends of its motion to open and close said valves, and a bit carried by the lower end of said other member. 3. A hardness tester comprising, a, body having a, pair of reciprocable members mounted therein,.one of said members having. a driving engagement with the other of said members to angularly advance the other of said members, passages formed in said body for applying a vacuum to said members to retract said members, a valve for venting said passages to break the vaccum therein, valve actuating mechanism engageable with the otherof said members at the ends of its motion to open and close said valve, and a bit carried by the lower end of said other member.

14. A hardness testing machine comprising, a vertical adjustablebody member having a vertically reciprocable ram mounted therein, vacuum means for retracting said ram, a valve means actuated by said ram for rendering said vacuum means inoperative, a gage pivotally mounted on said body and swingable against a fixed stop. on said body andhaving an actuating member, a downwardly facing shoulder on said ram, a gage lever pivoted on said body and engageable with said shoulder and with said gage actuating member to actuate said gage and indicate variations in the distance between said stop and said shoulder, and spring means urging said gage and said lever out of measuring engagement with said ram whereby. impact shocks of said ram are not transmitted to said gage.

15. A hardness testing machine comprising, a vertical adjustable body member having a vertically reciprocable ram mounted therein, vacuum means for retractin said ram, a valve means actuated by said ram for rendering said vacuum means inoperative, a gage movably mounted on said body and movable against a fixed stop on said body, a shoulder on said ram, a gage lever pivoted on said body and engageable with said shoulder and'with said gage to actuate said ease and indicate variations in the distance between said stop and said shoulder, a spring means urgin said gage and said lever out of measuring engagement with said ram whereby impact shocks of said ram are not transmitted to said gage.

16. A hardness testing machine comprising a body having a cylinder formed therein, a ram reciprocable in said cylinder, vacuum means for retracting said ram, valve means automatically actuated by said ram at the ends of its reciprocating motion for intermittently rendering said vacuum means inoperative on said ram, means for rotating said ram through equal angular increments with each stroke of the ram, a rotary member having a non-rotative connection to said ram and angularly advanced with each stroke of said ram, a starting lever for controlling said vacuum means and having an interlocking engagement with said rotary member in the starting position of said rotary member and the offposition of said lever, and a shut-01f member connected to said lever and operatively engageable with said valve means in the off position of said lever to hold said valve means in position to render said vacuum means inoperative.

17. A hardness testing machine comprising a body having a cylinder formed therein, a ram reciprocable in said cylinder, fluid pressure means for retracting said ram, valve means automatically actuated by said ram at the ends of its reciprocating motion for intermittently rendering said pressure means inoperative on said ram, means for rotating said ram through equal angular increments with eachstroke of the ram, a rotary member having a non-rotative connection to said ram andangularly advanced with each stroke of said ram and a control member for controlling said pressure means and having an interlocking engagement with said rotary member in the starting position of saidtrotary member and the off-position of said control member, said control member being .urged to'off position by fluid pressure.

- ERNEST H. SHAFF.

REFERENCES CITED The following references are of record in the file of this patent: 1

UNITED STATES PATENTS Number Name Date 280,668 Rawlins July 3, 1883 1,121,050 Shore Dec. 15, 914 1,830,842 La Vercombe Nov. 10, 1931 2,003,863 Melton et a1. June 4, 1935 2,037,527 Melton et al Apr. 14, 1936 2,109,521 Ballentine Mar. 1 1938 2,427,151 Mick Sept. 9, 1947 

